I'm trying out Kwant, and I've encountered a problem when investigating
The simplest minimal example would be to take your file
"quantum_wire_revisited.py", set W=1 there, and change the energy window to
energies=[0.01 * i for i in xrange(1000)]
The lattice is plotted correctly, but the conductance calculation yields
a "ValueError: expected square matrix".
Changing "kwant.lattice.square" to "kwant.lattice.chain" does not solve
the problem. Can you reproduce the error, or could there be a problem
with my Kwant installation?
Dr. Thomas Schmidt Department of Physics
Klingelbergstrasse 82 Phone: +41 61 267 3751
CH-4056 Basel Email: Thomas.L.Schmidt(a)gmx.de
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The object kwant.physics.PropagatingModes returned by the method
modes() of a finalized infinite system has the wave functions of all
the propagating modes. These wave functions are defined within a
single unit cell of the lead, that's why I call them transverse.
On Wed, Dec 4, 2013 at 10:16 PM, Benoit GAURY <benoitgaury(a)gmail.com> wrote:
> Hi Anton,
> I'm not sure I understand what you mean when you write "the transverse
> profile of the edge states". I was looking for a transverse wave function
> this afternoon, with in mind the calculation of <x>, the average of the
> position operator. I was not able to get the correct wave function though.
> So, are you saying that my method is ok with the wave function you mention?
> 2013/12/4 Anton Akhmerov <anton.akhmerov(a)gmail.com>
>> Hi Gaury,
>> It's relatively simple: you can just make an infinite stripe with
>> magnetic field, finalize it, and get access to the propagating states
>> at the Fermi level using the modes() method. This will give you access
>> to the transverse profile of every edge state (together with their
>> momentum and velocities, see
>> Note however that this is rather inaccurate, since to get the correct
>> positions of the edge states one needs to take electrostatics into
>> account, something that is not yet available in Kwant.
>> On Wed, Dec 4, 2013 at 7:45 PM, GAURY Benoit 229701 <Benoit.GAURY(a)cea.fr>
>> > Hello everyone,
>> > I am currently working on the quantum Hall regime. More precisely I want
>> > to
>> > know the position of the edge states from the edges my sample. Say I
>> > have a
>> > bar connected to two leads. Is the integration of the charge density
>> > over
>> > energy the best way to find the location of the edge states?
>> > I was wondering if the average of the position operator was something
>> > accessible.
>> > Do you guys have any thoughts on that?
>> > Benoit
I am currently working on the quantum Hall regime. More precisely I want to know the position of the edge states from the edges my sample. Say I have a bar connected to two leads. Is the integration of the charge density over energy the best way to find the location of the edge states?
I was wondering if the average of the position operator was something accessible.
Do you guys have any thoughts on that?
Kwant is very helpful for define a hamiltonian matrix (with
.hamiltonian_submatrix()) and plot a wave function (with
.plotter.map()). But how know where is a site in the matrix? for example
for do a 1D plot of wave function in a special direction?
Thanks in advance,